Patent Application
20210310371
The present disclosure generally relates to a compressor and, more particularly, relates to a motorized compressor device with an air bearing having reduced axial and radial stack-up.
Turbomachines generally include a housing and a rotating group housed therein. The rotating group includes a wheel that opposes a shroud surface of the housing to define a fluid gap therebetween. The fluid gap, during operation of the machine, receives a fluid flow. The fluid gap is an important feature as it affects performance of the turbomachine. In many cases, a smaller fluid gap leads to increased efficiency during operation.
However, manufacturing and/or design of these turbomachines presents certain problems. For example, the turbomachine includes a plurality of parts, and the assembly of parts can create an excessive tolerance stack-up. Tolerance stack-up represents the worst-case cumulative effect of part tolerance with respect to an assembly. Since the fluid gap is an important feature of a turbomachine, the tolerance stack-up of the assembly is compared to the available fluid gap between the wheel of the rotating group and the shroud surface of the housing. In some cases, if the tolerance stack-up is excessive, then the fluid gap is likely to be larger, which can detrimentally affect performance of the turbomachine.
Thus, it is desirable to provide a turbomachine that has a reduced tolerance stack-up. It is further desirable for the turbomachine to be compact and highly manufacturable. Other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background discussion.
In one embodiment, a turbomachine is disclosed that includes a housing assembly. The housing assembly includes a first housing member with a shroud surface, a bearing housing, and a second housing member. The turbomachine also includes a rotating group with a wheel that opposes the shroud surface to define a fluid gap therebetween. The turbomachine further includes a bearing that supports rotation of the rotating group within the housing assembly about an axis of rotation. At least part of the bearing is housed by the bearing housing. The first housing member has a first axial surface and the bearing housing has a second axial surface that is substantially flush with the first axial surface. The second housing member has a third axial surface facing in an axial direction opposite that of the first and second axial surfaces. The first housing member has a first radial surface and the bearing housing has a second radial surface. The first and second radial surfaces face in opposing radial directions relative to the axis of rotation. The first housing member and the bearing housing are attached to the second housing member with the fluid gap defined between the wheel and the shroud surface. The first and second axial surfaces abut against the third axial surface, and the first radial surface abuts against the second radial surface.
In another embodiment, a motorized compressor device is disclosed that includes a housing assembly. The housing assembly includes a compressor housing with a shroud surface, a bearing housing, and a motor housing. The compressor device also includes a rotating group with a compressor wheel that opposes the shroud surface to define a fluid gap therebetween. Furthermore, the compressor device includes an air bearing that supports rotation of the rotating group within the housing assembly about an axis of rotation. At least part of the air bearing is housed by the bearing housing. The compressor device also includes an electric motor housed within the motor housing. The electric motor is configured to drivingly rotate the rotating group within the housing assembly. The compressor housing has a first axial surface and the bearing housing has a second axial surface that is substantially flush with the first axial surface. The motor housing has a third axial surface facing in an axial direction opposite that of the first and second axial surfaces. The compressor housing has a first radial surface and the bearing housing has a second radial surface. The first and second radial surfaces face in opposing radial directions relative to the axis of rotation. The compressor housing and the bearing housing are attached to the motor housing with the fluid gap defined between the compressor wheel and the shroud surface. The bearing housing at least partially encloses the electric motor within the motor housing. The first and second axial surfaces abut against the third axial surface, and the first radial surface abuts against the second radial surface.
In a further embodiment, a method of manufacturing a turbomachine is disclosed. The method includes attaching a first housing member with a shroud surface to a second housing member with a rotating group disposed therein. The rotating group has a wheel that opposes the shroud surface to define a fluid gap therebetween. The method also includes attaching a bearing housing to the second housing member. A bearing is at least partly housed by the bearing housing. The bearing supports rotation of the rotating group about an axis of rotation. The first housing member has a first axial surface and the bearing housing has a second axial surface that is substantially flush with the first axial surface. The second housing member has a third axial surface facing in an axial direction opposite that of the first and second axial surfaces. The first housing member has a first radial surface and the bearing housing has a second radial surface. The first and second radial surfaces face in opposing radial directions relative to the axis of rotation. The first housing member and the bearing housing are attached to the second housing member with the fluid gap defined between the wheel and the shroud surface. The first and second axial surfaces abut against the third axial surface, and the first radial surface abuts against the second radial surface.
The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
Broadly, example embodiments disclosed herein include a turbomachine with a housing and a rotating group housed therein. The rotating group has a wheel that opposes a shroud surface of the housing, and a fluid gap is defined therebetween. The turbomachine of the present disclosure has a relatively low number of components and the tolerance stack-up of these parts assembled together is relatively low. Specifically, there are relatively few parts affecting the radial and/or axial positioning of the wheel relative to the shroud surface. Thus, variability between parts has less effect on the fluid gap dimensions. Also, the manufacturability of the turbomachine is increased as a result. Ultimately, more efficient turbomachines can be produced because turbomachines with reduced fluid gaps can be repeatably made in high volume.
Referring initially to
The rotating group 118 may generally include an elongate, cylindrical shaft 140 with a first end 142 and a second end 144. The rotating group 118 may also include one or more wheels, such as a compressor wheel 130 that is supported on the first end 142 of the shaft 140 and a turbine wheel 131 that is supported on the second end 144. The housing assembly 119 includes a variety of parts that cooperatively house the rotating group 118. Cooperatively, the housing assembly 119 and the rotating group 118 defines various sections of the turbomachine 101, such as a motor section 112, a compressor section 110, and a turbine section 113.
The turbomachine 101 may be operatively connected to a fuel cell system 100 and may be configured as an e-charger or electric motorized compressor device for the fuel cell system 100. However, it will be appreciated that the turbomachine 101 may configured differently from the embodiments shown and that the turbomachine 101 may be incorporated in another system without departing from the scope of the present disclosure. The fuel cell system 100 may include a fuel cell stack 104 containing a plurality of fuel cells. Hydrogen may be supplied to the fuel cell stack 104 from a tank 106, and oxygen may be supplied to the fuel cell stack 104 to generate electricity by a known chemical reaction. The fuel cell stack 104 may generate electricity for an electrical device, such as an electric motor 105. In some embodiments, the fuel cell system 100 may be included in a vehicle, such as a car, truck, sport utility vehicle, van, motorcycle, etc. Therefore, in some embodiments, the electric motor 105 may convert the electrical power to mechanical power to drive and rotate an axle (and, thus, one or more wheels) of the vehicle.
Oxygen may be provided to the fuel cell stack 104, at least in part, by the turbomachine 101. More specifically, the motor section 112 may drive rotation of the rotating group 118, and the compressor section 110 may provide a compressed air stream to an intercooler 128 as it flows to the stack 104, and exhaust from the stack 104 may be fed back to the turbine section 113 for providing power assist to the motor section 112. It will be appreciated, however, that other embodiments of the turbomachine 101 fall within the scope of the present disclosure. For example, in some embodiments, the turbine section 113 may be omitted such that the turbomachine 101 includes the motor section 112 as well as the compressor section 110. Additionally, in some embodiments, the turbomachine 101 may include a plurality of sections, such as a plurality of compressor sections that are fluidly connected in succession to include a first (low pressure) stage that feeds a second (high pressure) stage that ultimately feeds the fuel cell system 100. Additional embodiments of the turbomachine 101 may be provided in other systems (other than the fuel cell system 100) without departing from the scope of the present disclosure.
Components of the motor section 112, compressor section 110, and turbine section 113 will now be discussed according to example embodiments. These details are illustrated in
The motor section 112 may include an electric motor 134 for driving rotation of the rotating group 118 and/or converting rotational power of the rotating group 118 into electrical power. The motor 134 may generally include a rotor 136 and a stator 138 of a known type. The rotor 136 may be mounted on the shaft 140, and the stator 138 may encircle the rotor 136. The first end 142 and second end 144 of the shaft 140 may extend from respective axial sides of the motor 134 and may be supported in a motor housing 150 of the housing assembly 119. The motor housing 150 may be hollow and/or may include a motor cavity 129 that receives the motor 134. In some embodiments, the motor housing 150 may include a hollow base body 135 with a first, open axial end 137 and a substantially closed second axial end 139 (
As shown in
The compressor housing 152 may include an axial face 108 that opposes an axial face 156 of the base body 135 of the motor housing 150. Portions of the axial face 108 may be attached and/or mate against the axial face 156 as will be described in detail below. At least some of the mating surfaces may be ground, polished, or otherwise conditioned to provide a predetermined surface roughness, smoothness, or other characteristic that ensures robust attachment. The compressor housing 152 may be fixed to the base body 135 of the motor housing 150 and may cover over a front side 146 of the compressor wheel 130. A back side 148 of the compressor wheel 130 may face toward the motor section 112. Accordingly, the compressor wheel 130 may be disposed within the compressor housing 152 and may directly oppose a shroud surface 155 of the compressor housing 152. The shroud surface 155 may be contoured inversely and according to the outer contour of the compressor wheel 130. The compressor housing 152 may also include a radially-inward facing inlet surface 181 disposed further upstream of the shroud surface 155 and the compressor wheel 130. Moreover, the compressor housing 152 may include a diffuser surface 183 disposed downstream of the shroud surface 155 and the compressor wheel 130 and that faces axially toward the motor section 112. The volute passage 154 may be disposed downstream of the diffuser surface 183.
As shown in
A fluid gap 180 may be defined between the wheel 130 and the shroud surface 155. More specifically, the fluid gap 180 may be defined radially between the shroud surface 155 and wheel 130 and axially from the leading end 182 to the trailing end 184 of the wheel 130. The fluid gap 180 may have a variety of shapes and dimensions without departing from the scope of the present disclosure. For example, the fluid gap 180 may have a constant width (measured normal to the shroud surface 155). Alternatively, the width of the fluid gap 180 may vary along its length as illustrated in
As shown in
During operation of the turbomachine 101, an inlet airstream (represented by arrows 122 in
Furthermore, in some embodiments, an exhaust gas stream (represented by arrow 132) from the fuel cell stack 104 may be directed back toward the turbomachine 101 and received by the volute inlet passage 192 of the turbine section 113. The exhaust gas stream 132 may, thus, drive rotation of the turbine wheel 131 before flowing to the outlet 194. Mechanical power from the turbine section 113 may be converted to electrical power for the motor 134 for ultimately assisting in rotation of the compressor wheel 130.
Referring now to
As mentioned above and as shown in
Embodiments of the bearing 121 are also shown in detail in
Furthermore, the journal bearing member 222 and the thrust bearing member 221 may be partially defined by and/or supported by structures of the housing assembly 119. For example, the housing assembly 119 may include a thrust cover 210 that supports the thrust disc 220. As shown in
Additionally, the housing assembly 119 may include a bearing housing 158. The bearing housing 158 may be a unitary, one-piece, annular part in some embodiments. As shown in
The bearing housing 158 may also include a bearing support portion 174 on an inner radial portion thereof for housing, supporting, and/or partly defining the bearing 121. The bearing support portion 174 may have a tapered and concavely contoured outer surface and may define a back side projection 179 that projects axially away from the first end 142 of the shaft 140. The bearing support portion 174 may include a front recess 178 at the axial face 160. Additionally, a radius of an inner diameter surface 175 of the bearing support portion 174 (including the projection 179) may remain substantially constant along its axial length.
The thrust cover 210 may be attached to the bearing housing 158 to cover over the thrust disc 220 within the recess 178. Specifically, the thrust cover 210 may be received in the bearing housing 158 with the surface 176 radially opposing the outer diameter portion 218. A sealing member 298 (e.g., an O-ring) may be received in the groove 219 to form a fluid seal between the opposing radial surfaces of the thrust cover 210 and the bearing housing 158. The back side 214 of the thrust cover 210 may also mate against an opposing axial surface of the bearing housing 158 at an interface 293 (
Also, the bearing housing 158 may be received partly within the motor cavity 129 of the motor housing 150. As shown, a stepped outer diameter surface 141 of the bearing housing 158 may be sealed against a corresponding inner diameter surface 143 of the motor housing 150 via one or more sealing member 145 (e.g., O-rings). The inner radial portion of the bearing housing 158, including the bearing support portion 174, may cover over the open axial end 137 of the base body 135 and the stator 138 contained within the motor cavity 129.
In addition, the outer radial edge flange 163 may be received axially between the compressor housing 152 and the motor housing 150 with the first axial surface 230 facing toward the compressor housing 152 and the second axial surface 232 facing toward the motor housing 150. Specifically, in some embodiments, the second axial surface 232 may abut, overlay, and/or overlap an opposing axial end surface 236 of the base body 135 of the motor housing 150. One or both surfaces 232, 236 may be a ground or polished surface that exhibits low surface roughness and high smoothness (i.e., ground or polished to a predetermined surface roughness or smoothness). These mating surfaces 232, 236 may extend normal to the axis 120 and circumferentially about the axis 120. In addition, these surfaces 232, 236 may be secured together via one or more fasteners 238 (e.g., bolts) extending axially therebetween.
Furthermore, the compressor housing 152 may be fixed to the base body 135 of the motor housing 150 and may be fit over the bearing housing 158. Specifically, the compressor housing 152 may include an outer axial surface 240 that abuts, overlays, and/or overlaps the axial end surface 236 of the base body 135. The outer axial surface 240 may be a ground or polished surface that exhibits low surface roughness and high smoothness (i.e., ground or polished to a predetermined surface roughness or smoothness) for mating against the axial end surface 236. These mating surfaces 240, 236 may extend normal to the axis 120 and circumferentially about the axis 120. In addition, these surfaces 240, 236 may be secured together via one or more fasteners 242 (e.g., nuts and bolts) extending axially therebetween.
The axial face 108 of the compressor housing 152 may further include a recess 244 (
Moreover, in this position, the first axial surface 161 of the bearing housing 158 and the diffuser surface 183 of the compressor housing 152 may face in opposite axial directions and may be separated apart at a distance to define a diffuser area 246 of the compressor flow path 151. The diffuser area 246 is disposed outward radially from the trailing end 184 of the compressor wheel 130 before the volute passage 154.
As shown in
This arrangement may have a reduced axial and/or radial tolerance stack-up affecting the fluid gap 180. In other words, there are relatively few parts in this arrangement, and they are arranged compactly such that there is a reduced tolerance stack-up affecting the fluid gap 180.
Specifically, as represented in
Furthermore, as represented in
Accordingly, the compressor section 110 is configured with a reduced number of features contributing to the radial and axial tolerance stack-up affecting the fluid gap 180. The motor housing 150 has little-to-no effect on the radial and/or axial tolerance stack-up of the fluid gap 180. Both the compressor housing 152 and the bearing housing 158 may register axially against the common surface 236; however, the motor housing 150 does not contribute to the radial stack-up affecting the fluid gap 180. In other words, the components of the compressor section 110 may be attached together to define the fluid gap 180 largely independent of the motor housing 150.
Thus, the compact arrangement of the compressor section 110 provides the advantages discussed above. For example, the compressor section 110 may be constructed such that the dimensions of the fluid gap 180 are held within tight tolerances. The part count can be relatively low. The compressor section 110 can also be manufactured at high volume in a repeatable manner.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the present disclosure. It is understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims.
